Can testing machine with magnetic can separating mechanism



Jan. 28, 1958 K. BOFINGER ETAL 9 3 CAN TESTING MACHINE WITH MAGNETIC CAN SEPARATING MECHANISM Filed April 3, 1953 4 Sheets-Sheet 1 lEllllIlllllllllllll IF a:

, INVENTORS KARL BOF/NGEE ALBERT c. JC/f/MWEG ,4 T TOENEYS K. BOFHNGER ETA]. 2,821,300

Jan. 28, 1958.

CAN TESTING MACHINE WITH MAGNETIC CAN S EPARATING MECHANISM Filed April 3, 1953 4 Shee ts-Sheet 2 Jan. 28, 1958 K. BOFHNGER EI'AL 2,821,300

' CAN TESTING MACHINE WITH MAGNETIC- CAN SEPARATING MECHANISM Filed April 5, 1953. 4 Sheets-Sheet s INVENTORS mm EOE/N659 ALBERT a. JCW/MWEG M km United States Patent CAN TESTING MACHINE WITH MAGNETIC CAN SEPARATIN G lVlECHANISM Karl Bofinger and Albert C. Schimweg, Cincinnati, Ohio, assignors to American Can Company, New York, N. Y., a corporation of New Jersey Application April 3, 1953, Serial No. 346,586

4 Claims. (Cl. 209-74) The present invention relates to machines for testing containers or cans for leaks by subjecting them to air or other fluid under pressure and has particular reference to a magnetic discharge mechanism which separates leaky containers or cans from nonleaky or good cans.

An object of the invention is the provision a can testing machine of a discharge mechanism wherein separation of leaky cans from good cans is effected by an arrangement of opposed permanent and electromagnets of dilferent strengths to produce a simplified novel construction which is easy to maintain and which is particularly adapted to high speed operation.

Another object is the provision of such a tester discharge mechanism wherein no moving parts other than the can feed devices are required, with the result that a smooth efiicient segregation of leaky cans from good cans is effected with a minimum mechanism and efiort.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a side elevation of the can discharge portion of a can testing machine embodying the instant invention, with parts broken away;

Fig. 2 is a transverse sectional view taken substantially along the broken line 2-2 in Fig. l, with parts broken away;

Fig. 3 is an enlarged side elevation of the lower portion of the apparatus shown in Fig. 1, with parts broken back and parts shown in section;

Fig. 4 is a top horizontal section of a cam detail shown in Fig. 3, with parts broken away;

Fig. 5 is a view similar to Fig. 3 with certain of the parts omitted:

Figs. 6 and 7 are vertical sections taken substantially along the lines 6-6, 7-7 in Fig. 3, with parts broken away;

Fig. 8 is an enlarged sectional detail taken substantially along the line 88 in Fig. 6; and

Fig. 9 is a schematic view of the control devices, including a wiring diagram of the electric apparatus used in connection with them.

As a preferred or exemplary embodiment of the instant invention the drawings illustrate principal parts of a can testing machine of the character disclosed in United States Patent 2,019,517 issued November 5, 1935, to M. E. Widell on Can Tester. In such a machine, a continuous procession of cans A rolling on their sides, enter the machine to be tested, by way of an inclined entrance chute 21 (Fig. 1). The cans are individually picked up from the chute 21 by a testing head 22 in which a can is clamped for testing. There are a plurality of these testing heads 22 mounted on the outer periphery of a carrier wheel 23 carried in a frame 24 constituting the main frame of the machine. The wheel 23 is rotated con- 2,821,300 Patented Jan. 28, 1958 tinuously in a counterclockwise direction, as viewed in Fig. l, in any suitable manner, preferably through a large ring gear 25 secured to the wheel, as disclosed in the above mentioned Widell patent.

The carrier wheel 23 carries the clamped cans A along a circular path of travel through the machine. During this travel the clamped cans A are tested for leaks. This is effected by introducing air under pressure into the cans, as explained in the above mentioned Widell patent. A leaky can is detected by a detector valve 27 (Fig. 1) containing a diaphragm 28 (Fig. 9) which moves upon disturbance from a predetermined balanced condition by reason of leakage of air from the can.

After testing, the cans are removed from the carrier wheel 23 by a continuously rotating discharge turret or star wheel 31 (Figs. 1, 2, 3 and 5) which preferably comprises a pair of spaced and parallel discs having a plurality of peripheral, spaced pockets 32 which receive the cans. The turret 31 carries the tested cans along a circular path of travel and discharges them, in accordance with the test result, into a good can chute 35 and a leaky can chute 34. These chutes 34, 35 guide the cans, rolling on their sides, to separate suitable places of deposit and thus segregate the leaky cans from the good cans.

In the instant invention, the separation of the leaky cans from the good cans is effected by a pair of opposed magnets or magnet guides, a permanent magnet 37 and an electromagnet 38 of greater magnetic attraction than the permanent magnet. The permanent magnet is utilized to attract and direct either leaky or good cans into one of the discharge chutes 34, 35 while the electromagnet, normally energized, attracts the other cans from the permanent magnet for delivery into the other of said discharge chutes. However, when the electromagnet is deenergized its attraction is less than that of the permanent magnet and the latter then continues to attract the cans and directs them to a said chute. The change of magnetic attraction of the electromagnet 38 is effected by the detector valve 27 and through a suitable time delay mechanism 41 so as to compensate for the time delay between the time of detection and the time of discharge of a leaky can.

Referring now in more detail to the drawings, the discharge turret 31 is located directly under the entrance chute 21 and adjacent the outer periphery of the carrier wheel 23 and is mounted on a turret shaft 43 (Figs. 1, 2, 3 and 5) journaled in bearings 44 formed in the machine frame 24. The shaft 43 and the turret 31 carried thereon are rotated in time with the carrier wheel 23 by a sprocket 45 (Figs. 2 and 5) secured to the shaft. The sprocket is driven by an endless chain 46 which operates over a driving sprocket 47 mounted on a driving shaft 48 journaled in a bearing bracket 49 carried on the machine frame 24. The driving shaft 48 is driven by a gear 52 which is mounted on the shaft and which meshes with the large ring gear 25.

As a can A, after being tested, approaches the discharge turret 31, it rides along a short guide rail 54 (Figs. 3 and 5) which-supports the can against displacement from its testing head 22 during unclamping of the can for discharge. This guide rail 54 is secured to auxiliary brackets 55 which are carried on a support bracket 56 mounted on the machine frame 24. In this exteriorly supported condition the can passes on to the discharge turret 31 and is picked up by the turret when the can enters one of the turret pockets 32. A curved guide rail 58 disposed adjacent the outer periphery of the turret 31 sweeps the tested unclamped can out of the testing head 22 as the head passes the turret, and retains the can in the turret pocket while the turret carries the can upwardly over the top of the turret along a circular path of travel.

At the top of the turret 31 the can A engages against and is attracted to the permanent magnet 37 hereinbefore 3 mentioned. This magnet preferably is a bar magnet which in the construction shownin the drawings is utilized to retain leaky'cans A in their turret pockets 32 for delive y intd the leaky'can chute 34'." For this purpose the pennaiient'bar magnet 37 is disposed between the discs of the turret 31 (see Fig. 2) and curves around theturret shaft 43'v (see Figs. 3 and'5) preferably for 90 degrees, in the space between the shaft and the bottoms or inner sides of pockets32 to follow closely the inner side of the path of travel of the cans in the turret. Below the 90 degree icurved portion of the; magnet, it extends downwardly toward the bottomof the leaky can chute 34. This magnet 37 is secured to the support bracket 56; V

The can chutes 34,35 are defined by a pair of vertically disposed parallel side plates 61 (Figs. 1, 2, 3 and S) spaced apart a distance slightly greater than the length of the cans Ate permit passage of the cans therebetween. The plates 61 aretied' together by an integral bottom wall 62 to provide'a unitary chute structure which is supported on a cross-rod 63 (as in'the above mentioned Widell patent) the ends of which are carried in the machine frame 24. The bottom wall 62 constitutes the bottom of the leaky can chute 34.

The good can chute 35 is disposed directly above the leaky can chute 34 and is defined by the side plates 61 and a pair of bottom'rails 64 which are secured to the inner faces ofthe side plates. These bottom rails 64 constitute the bottom of the good can chute 35. The inner ends of the rails 64 terminate in spaced relation to the outer periphery of the discharge turret 31, and thus provide a space or gap 65 of just suflicient dimensions to permit a leaky can A in a pocket 32 of the turret, to pass the end !of the rails for discharge into the leaky can chute 34.

Hence when a leaky can A is received'in'a pocket 32 of the discharge turret 31, the permanent magnet 37 retains the leaky can in its pocket until it enters the space or gap 65 adjacent the ends 'of the rails 64. While passing through this clearance space 65 the magnet 37 partially strips the leaky can out of its turret pocket and guides the can toward the bottom 62 of the leaky can chute 34. When the can engages against the chute bottom '62, it is pried loose from the magnet by the advancement of the turret, and the freed can rolls along the chute bottom to any suitable place of deposit for leaky cans.

In'the construction of the discharge mechanism illustr-atedin the drawings as a preferred embodiment of the invention, a good can A received in a pocket 32 of the discharge turret 31 is drawn away from the permanent magnet 37 as the can passes :over the'topo'f the turret and is' guided into thegood can chute 35. For this purpose the electrom'agnet 38 is normally maintained in an'energized condition. The electromagnet 38 is located adjacent "to the outer sides of the pockets 32 and is secured to a continuing, declining straight section 67 of the curved guide rail 58." This straight section 67 of the guide rail extends toward and above the good can chute 35, tangentially away from the circular path of travel of the can in the discharge turret 31 and bridges the gap 65 at the inner terminal ends of the bottom rails 64 of the good can chute. The electromagnet 38 preferably is disposed above this gap 65.

Hence the normally energized electromagnet 38 attracts the good can to it and thus draws it way from the permanent magnet 37. The rotation of the turret 31 and the declined position of the guide rail section 67 propel the can along the rail section while it is attracted thereto and thus passes over the gap 65 at the inner ends of the good can chute bottom rails 64. When the can is beyond this gap 65 is fallsonto the bottom rails 64 and is guided through the good can chute 35 to any suitable place of deposit for good cans. For a leaky can the electromagnet 38 is deenergized and the leaky can is thus held in the turret pocket 32 by the permanent magnet 37 and is delivered into the leaky can chute 34 as hereinbefore explained. In this manner the leaky cans are separated and segregated from the good cans so that they may be with held from shipment and storage.

Energizing and deenergizing of the elect-romagnet 38 is effected by the time delay mechanism 41 since a leaky can A is detected while it is still in its testing head 22 and before it reaches the discharge turret 31. Any suitable time delay mechanism will suffice for this control of the electromagnet. A preferred type of delay mechanism, as illustrated in the drawings comprises a rotatable timing wheel 71 (Figs. 3, 4, 6, 7, Sand 9) which is located in a box or casing 72 secured to the machine frame 24. The wheel 71 is mounted on a short horizontal shaft 73 journaled in a bear-ing 74 in the casing 72. Outside of the casing (Fig. 6) the shaft 73 carries a sprocket 75 which is rotated in time with the discharge turret 31, by an endless chain 76 (Figs. 2 and 3) driven by a sprocket 77 on the discharge turret shaft 43. Thus the timing wheel 71 is rotated in time with the discharge turret 31.

The timing wheel 71 carries a plurality of timing pins 81' each having an enlarged head 82. There is one of these timing pins 81"for each pocket 32 in the discharge turret 31. The pins 81 are disposed in transverse bores 83 extending through the wheel and arranged in a circle adjacent the outer periphery of the wheel. The heads 82 of the pins are all disposed on the outer face of the wheel in outwardly spaced relation thereto as best shown in Figs. 3 and 6, and the pins extend entirely through the wheel and project slightly beyond its inner face.

The timing pins 81 are adapted to be shifted axially in their bores 83 and to remain in this shifted position during a predetermined cycle of rotation of the timing wheel 71. To hold the pins in their shifted positions frictional pressure is exerted against the sides of the pins by spring barrels 85 (Fig. 8) located in sockets 86 formed in the edge of the wheel. The inner end of each spring barrel 85 extends into the adjacent bore 83 and engages against a flat 87 (see also Fig. 6)'formed on the timing pin. A compression spring 88 interposed between a barrel 85 and a set screw89 threadedly engaged in an enlargedportion of a socket '86 presses the barrel against a pin 81 and holds it in a shifted position.

Shifting of the timing pins 81 is effected only for leaky cans A as andwhen detected by the detector valve 27. This shifting of the pins 81 is efiected by a selector arm 91 (Figs. 3, 7 and 9) which depends adjacent the path of travel of the heads 82 of the timing pins 81 as they rotate with'the timing wheel '71. The selector arm 91 intermediate its ends is mounted on a pivot pin 92 secured in a bracket93 fastened to the inside of the casing 72. The lower end of the arm 91 isformed with a curved face shoe 94 for engagement with the 'heads 82 of the timing pins. The upper end of the arm is attached to a spring 95 which holds the shoe 94 of the arm in the path of travel of the pin heads 82-. A lug 96 extending from the upper end of the arm engages against a set screw 97-inthe bra'cket 93 and provides for limiting of the travel and adjustment of the position of the shoe 94 relative to the pin'heads 82.

Hence'as the head 82 of each 'pin 81passes the curved shoe 94 of the selector arm 91, during rotation of the timing wheel71', the pin heads push the shoe 94 outwardly away from'th'e timing wheel without any effect on the pins, 'as-long as the cans A being tested are detected by the detector valve 27' as good cans. When a leaky can A is detected by the detector valve 27, the selector arm 91 is temporarily locked against movement just prior to its engagement with the head 82 of the pin 81 which corresponds in position 'with the leaky can. This lbcking of theselector arm 91 is eifected by a locking wedge or member 101 (Figs. 3, 7 and 9) which is vertically movable into position between a locking lug 102fon'the back of the curved shoe 94 and an'adjacent spaced backing-up bracket or stop 103 which is L-s haped and extends out from the back wall of thecasing 72.

The locking wedge 101 extends up from a movable core 105 of a normally deenergized solenoid 106 located below the selector arm 91 and secured to the back wall of the casing 72. The solenoid 106 is connected into a detector circuit which includes the detector valve 27 and a source of electric current such as a generator 108 (Fig. 9). In this circuit one side of the solenoid 106 is connected by a wire 111 to a fixed contact 112 disposed adjacent and in spaced relation to the diaphragm 28 of the detector valve 27. The other side of the solenoid is connected by a wire 113 to the generator 108. The generator is also connected by a wire 114 to a movable contact 115 secured to the diaphragm 28.

When a leaky can A is detected by the detector valve 27 through an unbalancing of the diaphragm 28 as explained in the Widell patent hereinbefore mentioned, the diaphragm moves up and brings its contact 115 into engagement with the fixed contact 112 and this closes the circuit. Electric current from the generator 108 thereupon flows along the circuit and energizes the solenoid 106 and this causes its movable core 105 to move up and thus raise the locking wedge 101 into locking position against the shoe 94 of the selector arm 91. The timing pin 81 which immediately engages the shoe 94 is thus pushed inwardly by the immovable shoe and is thus set to cause a deenergizing of the electromagnet 38 after a predetermined time delay which terminates when the leaky can arrives at a place adjacent the electromagnet 38. In the drawings this time delay is substantially equal to the time it takes the leaky can to travel a distance substantially equal to the distance spanned by four pockets 32 of the discharge turret 31.

While the leaky can, after detection, travels this distance toward the electromagnet 38, the set or pushedin timing pin 81 is carried by the timing wheel 71, downwardly under the wheel toward a switch lever 118 (Figs. 3, 6 and 9) which is located under the wheel. The switch lever 118 is mounted intermediate its ends on a pivot stud 119 threaded into a bracket 121 secured to the back wall of the casing 72. One end of the lever 118 is backed up by a spring barrel disposed in a lug 124 on the bracket 121. This spring barrel urges the other or free end of the lever toward the timing wheel 71. The free end of the lever 118 is formed with a cam face 125 which is disposed in the path of travel of the timing pins 81 in the space between the timing wheel and the heads 82 of the pins as best shown in Fig. 6.

Under normal rotation of the timing wheel 71, the switch lever 118 remains stationary but when a timing pin 81 is set for a leaky can A, the head 82 of the pin is located in alignment with the cam face 125 of the lever and hence as this pin passes the cam face, the head of the pin engages the cam face and pushes it outwardly as shown in Fig. 9. This rocks the timing lever 118 into engagement with a movable element 127 of a normally closed timing switch 128 secured to the bracket 121 and thus opens the switch.

The switch 128 is connected by wires 131, 132, 133 (Fig. 9) to the electromagnet 38 and to a suitable source of electric current such as a generator 134. This opening of the switch 128 breaks the circuit connecting with the electromagnet 38 and thus temporarily deenergizes the electromagnet to permit the leaky can A to remain attracted to the permanent magnet 37 for delivery into the leaky can chute 34 as hereinbefore explained. The period of time the electromagnet 38 is held deenergized is just suificient to permit the leaky can to pass out of range so that the leaky can will not be reattracted to it when it is reenergized for a following good can. This is controlled by the length of the cam face 125 on the switch lever 118.

When the head 82 of the set timing pin 81 rides off the cam face 125 of the switch lever 118, the lever rocks back into its original position and this closes the switch 128 and reestablishes the circuit. This reenergizes the electromagnet 38 for the delivery of good cans into the good can chute 35.

As the set timing pin 81 is carried around with the timing wheel 71 after passing the switch lever 118, it is reset or pushed out into its normal position for reuse when again selected by a leaky can. This resetting of the pin is effected before it again passes the shoe 94 of the selector arm 91 and is brought by a stationary reset earn 136 (Figs. 3, 4 and 6). This cam is secured to the back wall of the casing 72 and is disposed adjacent the path of travel of the inner ends of the timing pins at the top of the wheel so that it will be engaged by these ends of the pins and the pins thus pushed outwardly into their normal positions.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

We claim:

1. In a machine for testing containers to determine which are acceptable and which are unacceptable, the combination of a rotatable discharge turret having a pocket for receiving a tested container and advancing it in an arcuate path, an acceptable container chute and an unacceptable container chute disposed adjacent said turret, a permanent magnet guide disposed adjacent said turret and comprising a curved portion and a tangential Portion extending therefrom, said curved portion being disposed adjacent to and in substantial conformity with the inner side of said arcuate path of the container for retaining the container in said turret pocket and said tangential portion extending toward said unacceptable container chute for stripping the container from said pocket and directing it to said unacceptable container chute, a normally energized electromagnet guide disposed on the opposite side of said container path in opposition to said permanent magnet guide and extending in a direction divergent therefrom, said electromagnet guide having a magnetic attraction greater when energized and lesser when deenergized than that of said permanent magnet guide, said energized electromagnet guide attracting acceptable containers from said permanent electromagnet guide and directing them into said acceptable container chute, and means responsive to an unacceptable container for temporarily deenergizing said electromagnet guide for an unacceptable container whereby the unacceptable container remains attracted to said permanent magnet guide and is directed thereby to said unacceptable container chute.

2. In a machine for testing containers to determine which are acceptable and which are unacceptable, the combination of conveyor means for advancing tested containers, a permanent magnet disposed on one side of said advancing containers and extending toward a first place of deposit, an electromagnet disposed on the opposite side of said advancing containers in opposition to said permanent magnet and extending in a divergent direction toward a second place of deposit, said electromagnet when in deenergized condition having a lesser magnetic attraction than said permanent magnet and being ineffective to pull a container away from said permanent magnet whereby the container is maintained under the control of said permanent magnet and directed by said permanent magnet to said first place of deposit, said electromagnet when in energized condition having a greater magnetic attraction than said permanent magnec and being effective to pull a container away from said permanent magnet whereby the container is brought under the control of said electromagnet and directed by said electromagnet to said second place of deposit, said electromagnet normally being maintained in one of said conditions so that all acceptable cans are directed to one said place of dep osig "andmeans responsive to each unacceptable can for establishing Said other condition in said electromagnet so that each unacceptable can is directe'dto the other'said pl'ace of deposit,

3. The machine of claim- 2, wherein said Conveyor means comprises a rotatable discharge turret having a pocket forreceiving a tested container and wherein one of said magnets is disposed adjacent the inner side of said pocket and the" other of said magnets is disposed adjacent the'outer side of said pocket.

4. Thema'chin'eof claim 3 wherein the magnet disposed adjacent the inner side of said turret pocket is the outer side of said pocket is the electromagnet, said elec tromagne't being-normally maintained in energized condition so that all acceptable containers are brought under its control, said electromagne't being deenergized by the permanent magnet and the magnet disposed adjacentthe means responsive to each unacceptable container eachtime an-unacceptable :container :is detected so that: all unacceptablecontainers are maintained under the control of the permanent magnet.

References Cited'in the file of this patent- UNITED STATES PATENTS 2,101,129 Cameron Dec, 7, 1937 2,217,342' Ladrach' Oct. 8,1940 2,303,526 Cummings'et a1. Dec. 1, 1942 2,312,357 Odquist et a1. Mar. 2, 1943 2,353,748 Nordquist July 18, 1944 2,430,526 Mii'field'et a1. Nov. 11, 1947 2,696,107 Leisk Dec. 7, 1954 2,700,465 Pechy et al. -n Jan.'25, 1955 2,702,120 Nordquist Feb; 15,1955 2,729,329 Pechy Jan. 3, 1956 2,743,001 Nordquist' Apr; 24,1956 2,773,595 We'stin Dec; 11,1956 

